CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France.
Chem Soc Rev. 2021 Jul 5;50(13):7418-7435. doi: 10.1039/d1cs00196e.
Photochemical reactions are a key method to generate radical intermediates. Often under these conditions no toxic reagents are necessary. During recent years, photo-redox catalytic reactions considerably push this research domain. These reaction conditions are particularly mild and safe which enables the transformation of poly-functional substrates into complex products. The synthesis of heterocyclic compounds is particularly important since they play an important role in the research of biologically active products. In this review, photochemical radical cyclization reactions of imines and related compounds such as oximes, hydrazones and chloroimines are presented. Reaction mechanisms are discussed and the structural diversity and complexity of the products are presented. Radical intermediates are mainly generated in two ways: (1) electronic excitation is achieved by light absorption of the substrates. (2) The application of photoredox catalysis is now systematically studied for these reactions. Recently, also excitation of charge transfer complexes has been studied in this context from many perspectives.
光化学反应是生成自由基中间体的一种重要方法。通常在这些条件下不需要有毒试剂。近年来，光氧化还原催化反应极大地推动了这一研究领域的发展。这些反应条件特别温和和安全，能够将多功能底物转化为复杂产物。杂环化合物的合成尤为重要，因为它们在生物活性产物的研究中起着重要作用。在本文综述中，介绍了亚胺及相关化合物（如肟、腙和氯亚胺）的光化学自由基环化反应。讨论了反应机理，并展示了产物的结构多样性和复杂性。自由基中间体主要通过两种方式生成：（1）通过底物的光吸收实现电子激发。（2）现在系统地研究了这些反应的光氧化还原催化应用。最近，从多个角度研究了电荷转移配合物的激发在这方面的应用。
